Peonies from heaven

We have a large purple flower in our front yard. It bloomed over night. Jami is very excited by its presence among us, gracing the strip of lawn next to the mail box and between the sidewalk and the street. My knowledge of horticulture is limited. I love looking at nature, but I don't think about the names. So whenever I am able to place a name with a plant I have an inner satisfaction: now if ever in the future I am presented with a strange blossom, I can perform the "peony/not peony" test. I can say, "this is a peony" or failing that, "whatever this flower is, it is not a peony." Unless perhaps it might be a mutant peony.